Electronic switch for TV signal booster
a technology of electronic switch and tv signal, which is applied in the field of control of tv signal booster in tv tuner, can solve the problems of adding more noise to the original signal, reducing the component count, and easily deflecting the high frequency carrier, so as to achieve the effect of increasing the component coun
Inactive Publication Date: 2009-12-29
SONY EMCS MALAYSIA
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AI Technical Summary
Benefits of technology
This solution eliminates the need for manual switching, preventing picture interference by automatically disabling the LNA when a cable TV service is detected, ensuring better picture quality by distinguishing between off-the-air and cable TV signals.
Problems solved by technology
These high frequency carriers are easily deflected, reflected and blocked by obstructions such as concrete walls of buildings, trees and mountains.
However, as signal strengths from other television stations are often already more than sufficient, it may be necessary to turn the television signal booster off when the television receiver is receiving program from a television station with a strong signal.
Otherwise, the received RF signal will be over-amplified, causing the signal to saturate in the receiver's amplifier, adding more noise to the original signal.
If a television station broadcasts at a frequency sandwiched between two stronger television stations, turning on the booster while receiving signal from that station may result in signals from the adjacent television stations being amplified, causing interference and adding noise to the original signal.
Indeed, switching on a booster amplifier when connected to a cable television service most often causes interference by adjacent channels being amplified together and causing a noticeable beat effect on the TV picture.
Moreover, the lay user cannot be expected to understand that the booster can worsen his TV picture if it is switched on when not required, such as when a cable TV service is received.
Method used
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[0030]An example of a preferred embodiment of the present invention will be described with reference to the attached drawings, in which FIG. 1 describes a signal reception circuit including a tuner 2, a processing section 10 and a buffer 3. The processing section 10 has an IF converter 4, an AGC (Automatic Gain Controller) 6 and a microcontroller 8. Typically, the processing section 10 may be realized by utilizing an Ultimate One Chip (UOC) 10. The UOC is suitably a Philips TDA 12067 family TV processor chip. In this example of a preferred embodiment, the tuner 2 incorporates an integral LNA (booster amplifier) (not shown), that can be selectively switched on or off according to a control signal on line 11.
[0031]When the television is switched on, television signals from off the air or a cable TV service are received through RF input 1. The signals are downconverted to an IF frequency such as 38 MHz by the tuner 2 and enter the UOC 10.
[0032]The electronic switch of the present inven...
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A method of automatically disabling a low noise amplifier (LNA) that serves to boost weak video signals in a TV tuner, when the television receives a cable TV service. The method involves storing the total number of preset programs assigned during an initial auto-tune setup operation. If the total count exceeds a predetermined threshold, this indicates cable TV service whose signals will not require boosting. The LNA is then disabled to avoid interference between programs on neighboring channels.
Description
TECHNICAL FIELD[0001]The present invention generally relates to TV tuners, and more particularly, to controlling a signal booster in a TV tuner.BACKGROUND ART[0002]Television broadcasts are transmitted using high frequency RF carriers. These high frequency carriers are easily deflected, reflected and blocked by obstructions such as concrete walls of buildings, trees and mountains. As such, the strength of television broadcast signals varies greatly from one area to another. The quality of the reception of a given television station depends on many factors, including the location of the television receiver, the position of the television receiver, the quality and type (indoor or outdoor) of the receiving antenna used and the quality of the antenna cable used. The shielding effect of the antenna cable used will also have a substantial effect on the quality of a received television signal.[0003]Generally, in an area where the signal of a particular television station is considerably we...
Claims
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IPC IPC(8): H04N5/50H04N5/14H04N5/52
CPCH04N5/50H04N5/52
InventorTAN, SUI FENTAN, WAN JYHSAI, YOUKING, HON SIONG
OwnerSONY EMCS MALAYSIA